UN/NA Number Reference
DOT Class 6.1 Toxic Substance placard

UN 1889: Cyanogen bromide

49 CFR 172.101 Hazardous Materials Table·ERG 2024

DOT Classification and Shipping

UN 1889 is assigned the proper shipping name Cyanogen bromide in the U.S. DOT Hazardous Materials Table (49 CFR 172.101). It is classified as a Class 6.1 Toxic Substance material, Packing Group I. Required label(s): 6.1, 8.

Packing group indicates the degree of danger within a hazard class: PG I is high danger, PG II medium, PG III low. The proper shipping name, hazard class, UN number, and packing group together form the basic shipping description that must appear on shipping papers and, where required, on the package and placard.

Emergency Response (ERG Guide 157)

Hazards: TOXIC and/or CORROSIVE. Reacts with water. Non-combustible in themselves.

Fire: DO NOT use water. Dry chemical, CO2, dry sand.

Spill: Do not touch. Keep material dry.

Chemical and Physical Properties

Cyanogen bromide is a colorless to white crystalline solid with a penetrating odor. It is slightly soluble in water. It is gradually decomposed by water and very rapidly by acids to give off hydrogen bromide, a flammable and poisonous gas. Contamination with many materials can cause rapid decomposition of the material. It is toxic by inhalation of its vapors or by the hydrogen cyanide from decomposition or by ingestion. Toxic oxides of nitrogen are produced in fire involving this material. It is used in gold extraction, to make other chemicals, and as a fumigant.

CAS Number: 506-68-3
Molecular Formula: CBrN
Molecular Weight: 105.92 g/mol
Color / Form: White hygroscopic needles
Odor: Penetrating
Boiling Point: 142 F
Melting Point: 126 °F (EPA, 1998)
Flash Point: Not Applicable. Not flammable.
Autoignition: Not Applicable. Not flammable. (USCG, 1999)
Specific Gravity: 2.015 (sinks in water)
Vapor Pressure: 92 mmHg at 68 F
Vapor Density: 3.62 (heavier than air)
Water Solubility: In water, soluble with hydrolysis

Regulatory Data

CERCLA RQ (40 CFR 302.4)
1000 lb
EPCRA TPQ (40 CFR 355)
500 lb
RCRA Waste Code(s)
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A release of this material at or above its CERCLA reportable quantity (1000 lb) requires immediate notification to the National Response Center at 800-424-8802.

Special Provisions

49 CFR 172.102 special provision codes for this entry: A6, A8, T6, TP33, W31. These codes modify the general requirements (packaging, quantity limits, exceptions) for this specific material. Look up each code in 49 CFR 172.102 for the full text.

Need the full interactive record? Open UN 1889 in the SpillNerd lookup tool for the live database entry with placard graphics, GHS pictograms, full segregation tables, and synonym search. For another material, use the UN number and chemical lookup.

Reference data compiled from the DOT Hazardous Materials Table (49 CFR 172.101), the 2024 Emergency Response Guidebook, and public chemical databases (PubChem, NIOSH, EPA). Always verify the correct shipping description against the current regulation and the manufacturer's SDS Section 14 before shipping.